Artificial structural material and process of making it



finely powdered ash from the combustion oi. 45 Theprecise optimum proportions of'It-hese'in- Patented Aug. 14,1945 w YIUNITED A STATES VPATENT me'lelmgvv ARTIFICIAL STRUCTURAL MATERIAL AND PROCESS OF MAKING I'I Paul W. Jones and John W. Swezey, La Fayette,

Ind., assignors to Rostone Corporation, La. Fayette, Ind., a corporation of Indiana i No Drawing. Application September 11,1941,

Serial No. 410,431

4 Claims. (Cl. 106-118) It is the object of ourinvention to produce a an alkaline-earth base and water, withvthe solid 1 low-cost artificial structural material or synmaterials '11 in fi y commihllted' f m; thetic stone of increased strength, both against subject the moist mass to moist heat-t produce compression and against flexure, chemical reaction and induration.

Our present application is a continuation in he proportion of the alumino-silioic acid/mapart of our co-pending application Serial No. terial to the anhydrous alumino silicateimaterial' 149,274, filed June 19, 1937. may vary considerably. Any amount of itiis sur- Our new artificial structural material or synprising y l f m s i l as-' r s thetic stone is made mainly of anhydrous alu-, u ly p to abo t by W ight of the amo nt mino-silicate material, such as fly-ash or slag or of nhydrous alumino-silicate' material; Butv the pumice, with an alkaline-earth base and water, t m m amoun f r g t n n r s d st indurated under moist heat. To that extent, our 'at relatively little increased s s h 88 present invention follow the teaching of U, s. than that 70%, and varies, somewhat with the Patent No. 1,942,769, granted to Pefler and one P u ar alumino-silicicacid material mediad of us (Jo s) n January 9, 1934; on which patfor low-cost structural material othigh strength ent it isanimprovement. I we prefer to add between 1.5% and- 25% of the we have discovered that if in addition to the alumino-silicio o material-,os"itisin1thatrenae anhydrous alumino-silicate material we 'use in t We usually t p oportionate y the areatestthe mixture with the alkaline-earth base and the increase n tr ngth per unit weight. of-the more water a relativ l an amount hlumino. 20 costly added alumino-silicicv acid material; silicic acid material, we not only get an increase The alkaline-881th b35815 most comm? lime; n both compression and flexure strengths, but either h-c lcium or'dolo m'tic; and while'deth t th t i a i surprisingly great. surpris sirably of approximately suflicient amountand'no ingly much greater in proportion t t pro more for substantially complete reactionxwith the portion of added alumino-silicic acid material. alumino-silioio r al d't e hydrous While synthetic stone made of alumino-silicic olumino-siliooto Lit y in'pm tice v ry acid material, an alkaline-earth base, and water considerably in amount, 0111 are well-known as set forth in U. s. Patent No. 45% (in terms f hydr ted me) of the combined. granted to Peil'er, Harrison, and Ross Weight of the ao and hy m s 'on April 5, 1932-ngth1ng in connection with Such alumino-silicate materials, usuall with best repreviously known synthetic stone would lead one Sults if it is between 8% and25% of that comto expect that a small-addition or alumino-silicic billed Weight T appro imate mount of lime i t m in t mixture of anhydrous for maximum strength may be computed by addmine-silicate material, alkaline-earth material, s of the w zht'of-the aluminoesilicicacid and water would produce an increase in strength Q rial and 10% or the weight of the anhydrous S0 greatly in excess proportionately of the addi- 'aluminorsmcatematel'ial.

tr so made e The water should besumcient in amount'to By anhydrous alumino-silicate material" we produce r u tt ng. This is somewhatin a materials which contain, at least in n excess of the amount required for reaction, andis alumina and silica in combination, but which are 40 a y equal to between 15% and 25% of the generally considered as essentially having no total weight of the solid ingredients: The water water in their molecular constitution. Amon isdesirably added only after thersolidlingredients 7 this group of materials are various slags, clinker, have been thoroughly comminuted andxmlxed in and scoriae; and also (fly-ash, which is th dry formpowdered coal; and also various naturally occurredients vary somewhat; w h ifferent aluinino ring alumino-silicate minerals, like lava and silicic acid materials, and for: each such mateizial'--' pumice and volcanic ash. These materials, and a de e nati by t ay be ne yir xespeciallyvthe fly-ash, are relatively inexpensive, imum strength at minimum cost is'desire'd'. But so that their use involves low cost. although the optimum p op i n y r q r By" alumino-silicic acid material" we mean tests, our invention is not limited to optimum those naturally occurring materials, such as propo t ons; r marked d Surprisingoshales, slates, clays, gneiss, and schists, which ficial efiect on both compressive and flexural-Q contain, at least in part, one or more of the alustrengths, and on toughness; is' obtained" at. dismino-silicic acids, and also contain in part water proportionately low increase in cost when" any of constitution. amount of alumino-silicic acid material up even In carrying out our present invention we mix to of the amount of anhydrous aiuminoanhydrous alumina-silicate material and asmallsilicate material used is added to a mixture 0! er amouht of alumino-silicic acid material with anhydrousalumino-silicatematerial, an alkalineearth base, and water in making artificial structural material.

I fine), the alumino-silicic acid material, and the alkaline-earth base, are ground to desired fineness, preferably at least as fine as minus 200 mesh to minus 325 mesh per inch; and are thoroughly intermixed, desirably with all ingredients dry. Then the dry mixture is thoroughly mixed with the predetermined proportion oi water, as in a muller or awet pan, untilthe whole becomes a compact wetted mass in which there is intimate particle contact of colloidal or quasi-colloidal character. Then this wet mass is shaped as desired, as in molds, under pressure'and/or tamping if desired. Then the shapes (or shaped masses) are subjected to moist heat, conveniently steam under pressure, but without complete dryinE, l1

til the desired chemical reaction-among the in-' gredients is effected: Final complete drying may then be done, in the air or in an oven; but ordinarily this is neither desired nor necessary. I

Example 1 In one practical example of our process, 100 parts (by weight) of fly ash (here one obtained from the Detroit Edison Company), 2 to 20 parts I by weight of shale (here an Indiana knobstone shale) oontaining'alumino-silicic acid, and 10 to 20 parts of hydrated (slaked) lime, all of suificient fineness topass-through a 200 mesh or even through a 325'-mesh screen, are thoroughly mixed while dry. Then.15 to '25 partsoiwater are added; and'the whole is mixed, in'a'wet an or similar machine, to produce a thoroughly wetted quasi-colloidal mass. This wet mass is now formed into the desired shapes, usually'in molds; as by hydraulic pressing under pressure from 1500 to GOOO'pounds per square inch, or by heavy tampingeither on the mass itself or we cover plate laid over it. The shapedmass is now put inan' autoclave r indurating chamber; and, if desired after first being exposed to normal room. conditions ior 'several hours (as over night) although that need not be'done, is subjected ior fabout two hours to saturated steam at-a pressure of about 50 to 125 pounds per squareinch, conveniently about .75 pounds This steam may either be introduced into" the'indur'ating chamber.

'irom'outside, or be generated in the indu'rating;

chamberitseliaby heating 'the'latter. Duringv is two-v-hourinduration the desired chemical reac- I tiontalz ace, and the product reaches practically'jlts iull'strength and is'ready' for use; although drying after the induration produces some further increase in strength. 1 a

The product thus obtained is definitely stronger than one similarly made with-the shale omitted. This is clear from the following tables "A to H, in which the amounts oi. fly ash,'clay or shale, and. lime are given in rts by weight, and

the compressive and fiexural strengths are given,

inpounds per square inch:

' Table A 0 20 100 7.4 20 5, 415 100 0 o 20 5, sec 100 ms 20 e, 715 100 24.0 20 7,

Table B y h De- Bhale,Knob- I troit Edison stone Founm8!!- Flexurel o. taine Co.,lnd. mfinath I 100 0 2' 435 m0 .810 100 m .955 i% 23 ,3 egg 10 I I Table C Fly-ash De- .01

troit Edison near fiomb d 6, llllh- 00:11pm C0. M0, q celclum m1;

1m m aim mo .170 '20 9.0 m 30 m0 20 5,110 I .77s

Table D p y 8 h De- Ciay'from Lime sh- Flexuml mtg-:1? no rar r 0 6m strength 100 I 0 m 43 -4 m 2,640 100 0.0 20 a, 700 100 16.8 m 3,470 20 3,410 r I Table E y- ,De- Bllale,Knob. Ll troit Edison stone. Faunp ssive Co. taine 00., Ind. calcium strength 40 '26 a 015 100 6 157s 100 13 n 7 5,060 .rable'r'if I Fly-ash De- Shale,Knob. I I I troll: Edison stone Foun- Lime: Flexural 0o. taineOo.,Ind. ch11" str ngth 6 I 6 20 1,880 100 m m Table G Fly-ash msm xms troitEdison stone Foun- Lime f m I Table H;

' 0 10 use 25 20 2,010 50 50 so 2,005

In the testsbtlabl'es A tell, the dry materialswere thoroughly mixed by hand; an amount 01 water was used equal to 20% of the total weight oi the dry ingredients; and the amounts 75 oi lime in Tables G and H were 50% of the weight of shale plus 10% of the weight of flyash. The damp mixtures were pressed into the desired shapes at 2500 pounds per square inch in a hydraulic press, to produce a. 2-inch cubes. 12. bars measuring x 2 x inches.

The cubes and bars were indurated by being subjected for two hours to saturated steam at a pressure of 75 pounds per square inch. The 2-inch cubes were used for the compression tests, by crushing in a testing machine. The bars were used for the fiexure tests, by mounting them with a 4-inch clear span, and computing the fiexural strength by the formula in which P'==-the breaking load l=the span (4") b=the width (2") d=the thickness /2") Other ingredients may be included in addition to the alumino-silicic acid material, the anhydrous alumino-silicate material, the alkalineearth base, and the water. These other ingredients may be coarse aggregates, such "as crushed limestone, granite, marble, or the refuse called chats from lead and zinc ore; and/or they may be fibrous or lamellar material, such as asbestos, organic fibers, or mica; and/or they may be talc or gypsum; and/or they may be mineral pigments, if color is desired.

In addition, after induration the artificial structural material or synthetic stone produced may if desired be dried and impregnated, as with some water-repellant substance to prevent absorption of moisture, such for instance as oils or waxes, of either mineral or vegetable origin, or natural or synthetic resins.

But these latter things are incidentals. The fundamental thing is the added smaller amount 01' alumino-silicic acid material to the anhydrous alumino-silicate material, the alkalineearth base, and the water.

We claim as our invention:

1. The method of producing artificial structural material or synthetic stone, which consists in mixing anhydrous alumino-silicate material, an amount of alumirio-silicic acid material equal to between 1% and by weight 01' the amount of anhydrous alumino-silicate material, enough alkaline-earth base to produce reaction, and enough water to produce thorough wetting and form a compact wetted mass, with the solid ingredients all finely divided, and subjecting the mixture to induration under moist heat.

2. The method of producing artificial structural material or synthetic stone, which consists in mixing anhydrous alumina-silicate material, an amount of alumino-silicic acid material equal to between 1.5% and 25% by weight of the amount oi anhydrous alumino-silicate material, enough alkaline-earth base to produce reaction, and enough water to produce thorough wetting and form a compact wetted mass, with the solid ingredients all finely divided, and subjecting the mixture to induration under moist heat.

3. An artificial structural material or synthetic stone, comprising a compact mixture, indurated under moist heat, of anhydrous alumino-silicate material, an amount of alumino-silicic acid material equal to between 1% and 70% by weight of the amount of anhydrous terial, enough alkaline-earth base to produce reaction, and enough water to produce thorough wetting and form a compact wetted mass, with the solid ingredients all finely divided.

4. An artificial structural material or synthetic stone, comprising a compact mixture, indurated under moist heat, of anhydrous alumino-silicate material, an amount of alumino-silicic acid material equal to between 1.5%

and 25% by weight of the amount of anhydrous alumino-silicate material, enough alkalineearth base to produce reaction, and enough water to produce thorough wetting and form a compact wetted mass, with the solid ingredients all finely divided.

PAUL W. JONES. JOHN W. SWEZEY.

alumina-silicate ma-' 

